Question: A particular novel contains $40,\!000$ words. If the author completed the novel in $80$ hours, on average how many words per hour did she write?
Solution: We find the average words per hour by dividing the total words by the total hours. $$\frac{40,\!000\text{ words}}{80\text{ hours}}=\frac{4,\!000}{8}=\frac{40\cdot100}{8}=5\cdot100=\boxed{500} \text{ words per hour}$$